Nice work... can you post voltage measurements on 2k2 and 220R resistors in LTP colectors?
Regards
measurements
Hi, here are some measurements. I've corrected the offset by changing the 470R resistors. But I think now the amplifier is underbiased.
Advice are welcome
But the sound is very, very good. Deep, powerful bass, well balanced mids and transparent beautiful highs.
Regards Olaf
Hi, here are some measurements. I've corrected the offset by changing the 470R resistors. But I think now the amplifier is underbiased.
Advice are welcome
But the sound is very, very good. Deep, powerful bass, well balanced mids and transparent beautiful highs.
Regards Olaf
Attachments
Hi, here are some measurements. I've corrected the offset by changing the 470R resistors. But I think now the amplifier is underbiased.
Advice are welcome
But the sound is very, very good. Deep, powerful bass, well balanced mids and transparent beautiful highs.
Regards Olaf
Bias is set by voltage on 1N4148 diode and it is fixed, VAS current can not change bias.
Regards
Hi Still,
Thanks alot. And I have repeatedly tested it ...
You've completely right. But how can the amplifier then sound so good???
I will test it as soon as possible.
regards Olaf
I was wondering the same thing. I didn't come by the error by chance. I have the amp built and struggled for over a day trying to find what I did wrong until I sat down with the schematic and the layout and went over both of them with a highlighter. That is when I found it. I have only tested it without the outputs so far. If I have time I will solder in the outputs and mount it to a heatsink and do some official testing.
This layout was a little but of a struggle because the traces are very close together in places and I heated them a little too long so I had to do a bit of grinding to eliminate solder bridges. It looks like you have a newer layout that seems to have addressed some of these issues.
Blessings, Terry
This layout was a little but of a struggle because the traces are very close together in places and I heated them a little too long so I had to do a bit of grinding to eliminate solder bridges. It looks like you have a newer layout that seems to have addressed some of these issues.
Blessings, Terry
I have mine playing. Sound is distorted. Looks like oscillation on the scope. Also Both channel are drawing 40mA per rail. Just the front end and VAS draw 20mA so the outputs are biases very low. I don't have the zeners installed but I believe those are just for protection. Both channels sound the same so if I have an error it is on both channels but I have triple checked all the values due to the layout error.